Game Mechanics: Pulling while Invisible

[kanras]

Pending update:
- Added the distinction between direct and indirect hate.
- Mobs with indirect hate (obtained by another mob yelling for help) on a target cannot yell for help to transfer hate for their target to another NPC.
- The only way to prevent the transfer of direct hate to another nearby NPC is to be sneaking in the proper area of that NPC's visibility. Invis/IVU/Hide etc. no longer have any impact on whether direct aggro will be transferred.